It is well known to provide rear seat passenger compartments of vehicles with a seat belt that comprises of a shoulder belt in combination with a lap belt. The lap belt lies across the lap or waist of the passenger while the shoulder belt routes across the torso and shoulder of the passenger. It is known to utilize an anchor ring extending through a seat back for rerouting the path of a shoulder belt. It is also known to use a strap in conjunction with an elastic self-retracting feature for relieving the tension on a shoulder belt. It would be desirable to provide a detachable and slidable shoulder belt guide in conjunction with an elastic cord to adjust the routing of a shoulder belt over a passenger's torso while also providing a means to store the shoulder belt guide in a non-visible location when not in use.